What FIREs up star formation: the emergence of the Kennicutt–Schmidt law from feedback
What FIREs up star formation: the emergence of the Kennicutt–Schmidt law from feedback
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是什么引发了恒星的形成：反馈中肯尼卡特·施密特定律的出现
DOI：
10.1093/mnras/sty1241
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发表时间：
2018
影响因子：
4.8
通讯作者：
Quataert, Eliot
中科院分区：
文献类型：
--
作者：
Orr, Matthew E;Hayward, Christopher C;Hopkins, Philip F;Chan, T K;Faucher-Giguère, Claude-André;Feldmann, Robert;Kereš, Dušan;Murray, Norman;Quataert, Eliot
我们提出了一个分析的全球和空间分辨Kennicutt-Schmidt（KS）星星的形成关系的消防（反馈在现实环境中）的宇宙学模拟套件，包括晕与z = 0的质量范围从1010到1013 M。我们发现，KS关系出现，并保持强劲的反馈调节恒星形成气体的局部尺度的影响，独立于特定的小规模星星形成处方。我们证明了时间平均KS关系与红移和空间平均尺度相对无关，星星形成率面密度与金属丰度弱相关，与轨道动力学时间成反比.在恒定的星星形成率表面密度下，模拟星系的“冷而致密”气体表面密度（气体的T为< 300 K andn>10 cm−3，用作分子气体表面密度的替代）比在100 kpc尺度下观测到的小10.5 dex。这种差异可能是由于在模拟中为了屏蔽而低估了粒子尺度上的局部柱密度。最后，我们表明，在尺度大于单个巨型分子云，主要条件，确定是否发生星星形成是银河系盘的补丁是否是热托姆不稳定（而不是它是否是自屏蔽）：一旦补丁不能再热稳定对碎片，它崩溃，成为自屏蔽，冷却，并形成恒星，无论时代或环境。
We present an analysis of the global and spatially resolved Kennicutt–Schmidt (KS) star formation relation in the FIRE (Feedback In Realistic Environments) suite of cosmological simulations, including haloes withz= 0 masses ranging from 1010to 1013M⊙. We show that the KS relation emerges and is robustly maintained due to the effects of feedback on local scales regulating star-forming gas, independent of the particular small-scale star formation prescriptions employed. We demonstrate that the time-averaged KS relation is relatively independent of redshift and spatial averaging scale, and that the star formation rate surface density is weakly dependent on metallicity and inversely dependent on orbital dynamical time. At constant star formation rate surface density, the ‘cold and dense’ gas surface density (gas withT< 300 K andn> 10 cm−3, used as a proxy for the molecular gas surface density) of the simulated galaxies is ∼0.5 dex less than observed at ∼kpc scales. This discrepancy may arise from underestimates of the local column density at the particle-scale for the purposes of shielding in the simulations. Finally, we show that on scales larger than individual giant molecular clouds, the primary condition that determines whether star formation occurs is whether a patch of the galactic disc is thermally Toomre-unstable (not whether it is self-shielding): once a patch can no longer be thermally stabilized against fragmentation, it collapses, becomes self-shielding, cools, and forms stars, regardless of epoch or environment.